Genetics Part 3

Created by Morgan1023 

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Why are viruses referred to as obligate parasites?
A) They must use enzymes encoded by the virus itself.
B) Viral DNA always inserts itself into host DNA.
C) They can incorporate nucleic acids from other viruses.
D) They cannot reproduce outside of a host cell.
E) They invariably kill any cell they infect

D

Most human-infecting viruses are maintained in the human population only. However, a zoonosis is a disease that is transmitted from other vertebrates to humans, at least sporadically, without requiring viral mutation. Which of the following is the best example of a zoonosis?
A) herpesvirus
B) hepatitis virus
C) smallpox
D) HIV
E) rabies

E

A linear piece of viral DNA of 8 kb can be cut with either of two restriction enzymes (X and Y). These are subjected to electrophoresis and produce the following bands:
Cutting the same 8 kb piece with both enzymes will result in bands at 4.0, 2.5, 1.0, and 0.5. Of the possible arrangements of the sites given below, which one is most likely?
A) Y between 2 & 3, X between 4 & 5, and Y between 6 & 7.
B) Y between 2 & 3, X between 3 & 4, and Y between 7 & 8.
C) X between 3 & 4, Y between 4 & 5, and Y between 5 & 6.
D) Y between 2 & 3, Y between 3 & 4, X between 4 & 5.
E) Y between 0 & 1, X between 3 & 4, Y between 5 & 6.

B

Which of the following accounts for someone who has had a herpesvirus-mediated cold sore or genital flare-ups for the rest of life?
A) co-infection with an unrelated virus that causes the same symptoms
B) re-infection by a closely related herpesvirus of a different strain
C) copies of the herpesvirus genome permanently maintained in host cell cytoplasm
D) copies of the herpesvirus genome permanently maintained in host nuclei
E) re-infection by the same herpesvirus strain

D

Which of the following is characteristic of the lytic cycle?
A) Many bacterial cells containing viral DNA are produced.
B) The virus-host relationship usually lasts for generations.
C) The viral genome replicates without destroying the host.
D) A large number of phases is released at a time.
E) Viral DNA is incorporated in the host genome

D

Which of the following terms describes bacteriophage DNA that has become integrated into the host cell chromosome?
A) intemperate bacteriophages
B) plasmids
C) transposons
D) prophages
E) T-even phages

D

What is the name given to viruses that are single-stranded RNA that acts as a template for DNA synthesis?
A) viroids
B) lytic phages
C) bacteriophages
D) proviruses
E) retroviruses

E

What is the function of reverse transcriptase in retroviruses?
A) It translates viral RNA into proteins.
B) It uses viral RNA as a template for DNA synthesis.
C) It hydrolyzes the host cell's DNA.
D) It uses viral RAN as a template for making complementary RNA strands.
E) It converts host cell RNA into viral DNA.

B

Which of the following can be effective in preventing viral infection in humans?
A) taking nucleoside analogs that inhibit transcription
B) applying antiseptics
C) taking antibiotics
D) getting vaccinated
E) taking vitamins

D

You isolate an infectious substance that is capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus, or viroid. You have four methods at your disposal that you can use to analyze the substance in order to determine the nature of the infectious agent.
I. treating the substance with nucleases that destroy all nucleic acids and then determining whether it is still infectious
II. filtering the substance to remove all elements smaller than what can be easily seen under a light microscope
III. culturing the substance by itself on nutritive medium, away from any plant cells
IV. treating the sample with proteases that digest all proteins and then determining whether it is still infectious.
If you already knew that the infectious agent was either bacterial or viral, which treatment would allow you to distinguish between these two possibilities?
A) I
B) II
C) III
D) IV
E) either II or IV

C

You isolate an infectious substance that is capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus, or viroid. You have four methods at your disposal that you can use to analyze the substance in order to determine the nature of the infectious agent.
I. treating the substance with nucleases that destroy all nucleic acids and then determining whether it is still infectious
II. filtering the substance to remove all elements smaller than what can be easily seen under a light microscope
III. culturing the substance by itself on nutritive medium, away from any plant cells
IV. treating the sample with proteases that digest all proteins and then determining whether it is still infectious.
Which treatment would you use to determine if the agent is a prion?
A) I only
B) II only
C) III only
D) IV only
E) either I or IV

D

Which of the following represents a difference between viruses and viroids?
A) Viruses contain introns; viroids have only exons.
B) Viruses always have genomes composed of DNA, whereas viroids always have a genome composed of RNA.
C) Viruses have capsids composed of DNA, whereas viroids have no capsids.
D) Viruses cannot pass through plasmodesmata; viroids can
E) Viruses infect many types of cells, whereas viroids infect only prokaryotic cells.

C

The difference between vertical and horizontal transmission of plant viruses is that
A) vertical transmission is the transfer of DNA from one type of plant virus to another, and horizontal transmission is the exchange of DNA between two plant viruses of the same type.
B) vertical transmission is transmission of a virus from a parent plant to its progeny, and horizontal transmission is one plant spreading the virus to another plant.
C) vertical transmission is the spread of viruses from trees and tall plants to bushes and other smaller plants, and horizontal transmission is the spread of viruses among plants of similar size.
D) vertical transmission is the transfer of DNA from a plant of one species to a plant of a different species, and horizontal transmission is the spread of viruses among plants of the same species.
E) vertical transmission is the spread of viruses from upper leaves to lower leaves of the plant, and horizontal transmission is the spread of a virus among leaves at the same general level.

B

What are prions?
A) viruses that invade bacteria
B) viral DNA that has had to attach itself to the host genome
C) tiny molecules of RNA that infect plants
D) misfolded versions of normal brain proteins
E) a mobile segment of DNA

D

Which of the following characteristics, structures, or processes is common to both bacteria and viruses?
A) ribosomes
B) independent existence
C) cell division
D) metabolism
E) genetic material composed of nucleic acid

E

Emerging viruses arise by
A) the spread of existing viruses to new host species.
B) mutation of existing viruses.
C) the spread of existing viruses more widely within their host species.
D) all of the above.
E) none of the above.

D

Which enzyme was used to produce the molecule in Figure 20.1?
A) transcriptase
B) DNA polymerase
C) a restriction enzyme
D) RNA polymerase
E) ligase

C

Assume that you are trying to insert a gene into a plasmid. Someone gives you a preparation of genomic DNA that has been cut with restriction enzyme X. The gene you wish to insert has sites on both ends for cutting by restriction enzyme Y. You have a plasmid with a single site for Y, but not for X. Your strategy should be to
A) cut the plasmid with restriction enzyme X and insert the fragments cut with Y into the plasmid.
B) cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with the same enzyme.
C) insert the fragments cut with X directly into the plasmid without cutting the plasmid.
D) cut the plasmid with enzyme X and then insert the gene into the plasmid.
E) cut the plasmid twice with restriction enzyme Y and ligate the two fragments onto the ends of the DNA fragments cut with restriction enzyme X.

B

What is the enzymatic function of restriction enzymes?
A) to join nucleotides during replication
B) to repair breaks in sugar-phosphate backbones
C) to join nucleotides during transcription
D) to add new nucleotides to the growing strand of DNA
E) to cleave nucleic acids at specific sites

E

How does a bacterial cell protect its own DNA from restriction enzymes?
A) adding methyl groups to adenines and cytosines
B) using DNA ligase to seal the bacterial DNA into a closed circle
C) reinforcing hte bacterial DNA structure with covalent phosphodiester bonds
D) forming "sticky ends" of bacterial DNA to prevent the enzyme from attaching
E) adding histones to protect the double-stranded DNA

A

What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium?
I. Transform bacteria with recombinant DNA molecule.
II. Cut the plasmid DNA using restriction enzymes.
III. Extract plasmid DNA from bacterial cells.
IV. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments.
V. Use ligase to seal plasmid DNA to nonplasmid DNA.
A) III, II, IV, V, I
B) III, IV, V, I, II
C) II, III, V, IV, I
D) IV, V, I, II, III
E) I, II, IV, III, V

A

Bacteria containing recombinant plasmids are often identified by which process?
A) producing antibodies specific for each bacterium containing a recombinant plasmid
B) using radioactive tracers to locate the plasmids
C) examining the cells with an electron microscope
D) exposing the bacteria to an antibiotic that kills cells lacking the resistant plasmid
E) removing the DNA of all cells in a culture to see which cells have plasmids

D

Bacteria that contain the plasmid, but not the eukaryotic gene, would grow
A) only in the broth containing both antibiotics
B) in the nutrient broth plus ampicillin, but not in the broth containing tetracycline.
C) in the broth containing tetracycline, but not in teh broth containing ampicillin.
D) in the nutrient broth without antibiotics only.
E) in all four types of broth

E

Bacteria containing a plasmid into which the eukaryotic gene has integrated would grow in
A) the nutrient broth, the ampicillin broth, and the tetracycline broth.
B) the nutrient broth only.
C) the ampicillin broth and the nutrient broth.
D) the nutrient broth and the tetracycline broth only.
E) all four types of broth.

C

Bacteria that do not take up any plasmids would grow on which media?
A) the nutrient broth and the tetracycline broth.
B) the nutrient broth and the ampicillin broth.
C) the nutrient broth only.
E) the tetracycline broth and the ampicillin broth.

D

A principal problem with inserting an unmodified mammalian gene into a bacterial plasmid, and then getting that gene expressed in bacteria, is that
A) bacteria translate polycistronic messages only.
B) bacteria cannot remove eukaryotic introns.
C) bacterial RNA polymerase cannot make RNA complementary to mammalian DNA.
D) prokaryotes use a different genetic code from that of eukaryotes.
E) bacterial DNA is not found in a membrane-bounded nucleus and is therefore incompatible with mammalian DNA.

B

The DNA fragments making up a genomic library are generally contained in
A) individual wells.
B) radioactive eukaryotic cells.
C) DNA-RNA hybrids
D) recombinant viral RNA.
E) recombinant plasmids of bacteria

E

A researcher needs to clone a sequence of part of a eukaryotic genome in order to express the sequence and to modify the polypeptide product. She would be able to satisfy these requirements by using which of the following vectors?
A) BAC to accommodate the size of the sequence
B) a modified bacteriophage
C) a YAC with appropriate cellular enzymes
D) a human chromosome
E) a bacterial plasmid

C

To introduce a particular piece of DNA into an animal cell, such as that of a mouse, you would find more probable success with which of the following methods?
A) transcription and translation
B) the shotgun approach
C) introducing a plasmid into the cell
D) infecting the mouse cell with a Ti plasmid
E) electroporation followed by recombination

E

Which of the following produces multiple identical copies of a gene for basic research or for large-scale production of a gene product?
A) reverse transcriptase
B) DNA ligase
C) gel electrophoresis
D) gene cloning
E) restriction enzymes

D

Which of the following seals the sticky ends of restriction fragments to make recombinant DNA?
A) restriction enzymes
B) gel electrophoresis
C) gene cloning
D) reverse transcriptase
E) DNA ligase

E

Which of the following is used to make complementary DNA (cDNA) from RNA?
A) reverse transcriptase
B) restriction enzymes
C) gene cloning
D) DNA ligase
E) gel electrophoresis

A

Which of the following separates molecules by movement due to size and electrical charge?
A) gel electrophoresis
B) DNA ligase
C) gene cloning
D) reverse transcriptase
E) restriction enzymes

A

The segment of DNA sown in figure 20.2 has restriction sites I and II, which crease restriction fragments A, B, and C. Which of the gels produced by electrophoresis shown below best represents the separation and identity of these fragments?
A) - B A C +
B) - C A B +
C) - B A C +
D) - C A B +
E) - A B C +

B

Which was developed by a British researcher and causes DNA sequences to be transferred to a membrane and identified with a probe?
A) RT-PCR
B) Northern blotting
C) Eastern blotting
D) Southern blotting
E) Western blotting

D

Which of the following is most closely identical to the formation of twins?
A) therapeutic cloning
B) use of adult stem cells
C) embryo transfer
D) cell cloning
E) organismal cloning

E

In 1997, Dolly the sheep was cloned. Which of the following processes was used?
A) use of mitochondrial DNA from adult female cells of another ewe
B) separation of an early stage of sheep blastula into separate cells, one of which was incubated into a surrogate ewe
C) replication and dedifferentiation of adult stem cells from sheep bone marrow
D) isolation of stem cells from a lamb embryo and production of a zygote equivalent
E) fusion of an adult cell's nucleus with an enucleated sheep egg, followed by incubation in a surrogate

E

Which of the following statements in consistent with the results?
A) A is the child of C and D.
B) B is the child of A and C.
C) D is the child of B and C.
D) A is the child of B and C.
E) C is the child of A and B.

E

Scientists developed a set of guidelines to address the safety of DNA technology. Which of the following is one of the adopted safety measures?
A) Genetically modified organisms are not allowed to be part of our food supply.
B) Transgenic plants are engineered so that the plant genes cannot hybridize.
C) Experiments involving HIV or other potentially dangerous viruses have been banned.
D) Recombinant plasmids cannot be replicated
E) Microorganisms used in recombinant DNA experiments are genetically crippled to ensure that they cannot survive outside of the laboratory.

E

Expression of a cloned eukaryotic gene in a bacterial cell involves many challenges. The use of mRNA and reverse transcriptase is a part of a strategy to solve the problem of
A) nucleic acid hybridization.
B) restriction fragment ligation.
C) electroporation.
D) post-translational processing.
E) post-transcriptional processing.

E

DNA technology has many medical applications. Which of the following is not done routinely at present?
A) genetic testing for carriers of harmful alleles.
B) production of viral proteins for vaccines
C) prenatal identification of genetic disease genes
D) introduction of genetically engineered genes into human gametes
E) production of hormones for treating diabetes and dwarfism

D

Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme?
A) AGTC
TCAG
B) AAAA
TTTT
C) AAGG
TTCC
D) ACCA
TGGT
E) GGCC
CCGG

E

In recombinant DNA methods, the term vector can refer to
A) a DNA probe used to identify a particular gene.
B) the enzyme that cuts DNA into restriction fragments.
C) the sticky ends of a DNA fragment.
D) a RFLP marker.
E) a plasmid used to transfer DNA into a living cell.

E

For mapping studies of genomes, most of which were far along before 2000, the 3-stage method was often used. Which is the usual order in which the stages were performed, assuming some overlap of the three?
A) linkage map, physical map, sequencing of fragments
B) sequencing of entire genome, physical map, genetic map
C) genetic map, sequencing of fragments, physical map
D) physical map, linkage map, sequencing
E) cytogenic linkage, sequencing, physical map

A

What is the difference between a linkage map and a physical map?
A) For a physical map, the distances must be calculable in units such as nanometers.
B) For a linkage map, markers are spaced by recombination frequency, whereas for a physical map they are spaced by numbers of base pairs (bp).
C) There is no difference between the two except the type of pictorial representation.
D) For a physical map, the ATCG order and sequence must be achieved, but not for the linkage map.
E) For a linkage map, it is shown how each gene is linked to every other gene.

B

Which of the following most correctly describes a shotgun technique for sequencing a genome?
A) physical mapping followed immediately by sequencing.
B) cloning large genome fragments into very large vectors such as YACs, followed by sequencing
C) genetic mapping followed immediately by sequencing
D) cloning several sizes of fragments into various size vectors, ordering the clones, and then sequencing them
E) cloning the whole genome directly, from one end to the other

D

What is proteomics?
A) the study of how a single gene activates many proteins
B) the study of the full protein set encoded by a genome
C) the linkage of each gene to a particular protein
D) the study of how amino acids are ordered in a protein
E) the totality of the functional possibilities of a single protein

B

Which of the following is a representation of gene density?
A) Humans have 27,000 bp in introns.
B) C. elegans has 20,000 genes.
C) Humans have 2,900 Mb per genome.
D) Humans have 25,000 genes in 2,900 Mb.
E) Fritillaria has a genome 40 times the size of a human.

D

If humans have 2,000 Mb, a specific member of the lily family has 120,000 Mb, and a yeast has 13 Mb, why can't this data allow us to order their evolutionary significance?
A) Size is comparable only within phyla.
B) Size does not compare to gene density.
C) Size matters less than gene density.
D) Size does not vary with gene complexity.
E) Size is mostly due to "junk" DNA.

D

Which of the following is a major distinction between a transposon and a retrotransposon?
A) A transposon moves via a DNA intermediate and a retrotransposon via an RNA intermediate.
B) A retrotransposon always uses the copy-paste mechanism, while a transposon uses cut and paste mechanism.
C) A transposon always leaves a copy of itself at its original position and a retrotransposon does not.
D) The positioning of a transposon copy is transient while that of a retrotransposon is permanent.
E) A transposon is related to a virus and a retrotransposon is not.

A

What is it about short tandem repeat DNA that makes it useful for DNA fingerprinting?
A) The sequence variation is acted upon differently by natural selection of different environments.
B) Every racial and ethnic group has inherited different short tandem repeats.
C) The number of repeats varies widely from person to person or animal to animal.
D) The sequence of DNA that is repeated varies significantly from individual to individual.

C

What is the most probable explanation for the continued presence of pseudogenes in a genome such as our own?
A) They are genes that had a function at one time, but that have lost their function because they have been translocated to a new location.
B) They are genes that have accumulated mutations to such a degree that they would code for different function products if activated.
C) They are genes with significant inverted sequences.
D) They are genes that are not expressed, even though they have nearly identical sequences to expressed genes.
E) They are duplicates or near duplicates of functional genes but cannot function because they would provide inappropriate dosage of protein products.

D

How might identical and obviously duplicated gene sequences have gotten from one chromosome to another?
A) by normal meiotic recombination
B) by chromosomal translocation
C) by transcription followed by recombination
D) by normal mitotic recombination between sister chromatids
E) by deletion followed by insertion

B

When does exon shuffling occur?
A) during mitotic recombination
B) as an alternative cleavage or modification post-translationally
C) as an alternative splicing pattern in post-transcriptional processing
D) as the result of faulty DNA repair
E) during splicing of DNA

C

Multigene families are
A) equivalent to the operons of prokaryotes.
B) usually clustered at telomeres.
C) identical or similar genes that have evolved by gene duplication.
D) groups of enhancers that control transcription.
E) sets of genes that are coordinately controlled.

C

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